As cable television operators (including satellite and terrestrial transmissions) provide more services to users, interactivity with the user is increasingly prevalent. For example, users can presently use “on demand” services to request a program and instantly watch that program on the television, without being required to wait for a predetermined start time for the desired program (as is the case with known “pay-per-view” systems). The user typically navigates a menu system under the control of a set top box (STB) to select a program. The user's selection is sent to the cable operator via a back channel, i.e., the channel carrying data from the end user to the cable operator, and the cable operator sends the requested program to the user's STB for further presentation on a connected display such as a standard television, high-definition television, plasma flat panel display, or the like. Other known interactive services include voting, betting, and ordering food, e.g., as provided by BskyB in the United Kingdom. A request is typically sent to the cable operator on the back channel, and the requested data is inserted in the broadcast stream back to the user.
Known back channel mechanisms include fixed telephone lines, Asymmetric Digital Subscriber Line (ADSL), DVB-RCC, and digital cable/cable modems. However, use of a fixed telephone line is not preferable because, obviously, the user cannot use the fixed telephone line when it is in use by the STB to communicate commands back to the cable operator. Likewise, the STB cannot communicate commands when the fixed telephone line is otherwise in use. A user can purchase a separate fixed telephone line for use as a back channel, but this incurs an often unwanted or unacceptable additional expense to the user. In addition, there is no way for a user using the STB to know whether the fixed telephone line is in use other than to pick up a telephone connected to the fixed telephone line and check for a dial tone, and a fixed telephone line or ADSL jack is often not physically located near the television set, making connection difficult, inconvenient, and more expensive.
While ADSL and cable-based solutions do not impose the same limitations as fixed telephone lines, ADSL and cable-based solutions presently do not have widespread coverage areas, or footprints (e.g., the “last mile” problem). In addition, it may take quite some time, e.g., a decade or more, before providers increase their respective footprints, due to expensive upgrade and installation costs for the necessary hardware and infrastructure by both the cable operator and end users. Contract and legal complexities have added to the delay of broadband interactive services as well.
Thus, it would be an advancement in the art to provide a back channel that does not require substantial infrastructure upgrade and investment. It would be a further advancement in the art to provide a mechanism to inform a STB user whether the back channel is available, when the back channel is not constantly available.